when you go on the hill bring a tool(screwdriver) and adjust as you take a couple of runs. If you feel comfortable in your living room strapped in you should be ok on the hill, FYI I ride 12/-12 and im comfy with that but it's all preference.
Do what feels right to you. No one has the perfect setup for everyone, but you have to find the perfect setup for you. I ride 15/-15, my husband rides 15/-7, everyone is different, get a little tool set and just tweek it as you go.